A fuel cell system is an example of a system that receives a supply of a fluid stored in a high-pressure fluid supply source, such as a high-pressure gas tank, via high-pressure piping and uses the fluid. In the fuel cell system, a fuel gas is supplied from a high-pressure gas tank that is filled with a hydrogen gas or natural gas, which serves as the fuel gas, at high pressure to a fuel cell via high-pressure piping. A plurality of valve devices are provided in the piping, whereby the supply pressure (amount of supply) of the fuel gas can be adjusted in stages.
Hydrogen or the like is used as a fuel gas in such a fuel cell system, and thus the handling of the fuel cell system needs to be considered sufficiently in terms of safety. In particular, gas leakage in the step of supplying the fuel gas needs to be prevented. For example, in patent document 1, it is proposed that a seal member of a high-pressure tank is provided with a temperature adjustor to avoid a reduction in the performance of the seal member.    Patent Document 1: JP2008-008378 A